ABSTRACT
The paper deals with peculiarities of forming colour images in both different types of information and various forms of art.

COMMUNICATORY FUNCTIONS OF COLOUR are realized in all the types of information. Those are ancillary functions of colour discrimination,
distinction, separation, combination and other universal functions that organize and activate perception of the principal content of
any information.

We consider cognitive and expressive functions of a colour image to be its principal "content" functions.

COGNITIVE FUNCTIONS OF COLOUR are realized when colour serves for mimetic reflecting some essential signs of real objects or for
marking (encoding) the principal concepts and ideas, as in scientific (and popular scientific) information, in conceptual-symbolic
and fine arts.

EXPRESSIVE FUNCTIONS OF COLOUR are realized when emotions having aesthetic meaning are conveyed by harmonic composition of the colour
image, as in art design, decorative art and, of course, in the music of colour.

Total colour image makes a triunity of the above functions. A hierarchy of functions within the triunity has many versions thus
resulting in colour variety of modi. Systemizing the range of colour images and formulating principles of harmonic colour designation
makes an urgent problem for colouring artistry of information. The paper poses this problem and also presents an attempt of solving
it theoretically.

1. INTRODUCTION

To clear the structure of colour modi a set of symbolic signs is coined:

and for the communicatory function
of colour (fccom) and black-and-white (fbwcom) information, respectively;

and for the cognitive function
of colour (fccog) and black-and-white (fbwcog) information, respectively;

and for the expressive function
of colour (fcexp) and black-and-white (fbwexp) information, respectively.

Then the relation between colour set of an information object (CSO) and the total colour modus (TCM) may be presented in such a way:

Thus two dual colour modi and two triple ones are obtained:

— purely cognitive colour modus,

— cognitive-expressive colour modus,

— purely expressive colour modus,

— expressive-cognitive colour modus.

2. COGNITIVE COLOUR MODUS

2.1. Let us consider the dual purely cognitive colour modus . one can see that
it has no expressive function. This fact by no means belittles its informativity, especially when it is used in scientific information
where "expressive noise" of emotionality may but draw one away from understanding an objective content. Most often this modus is
formed by encoding colour signs that give a symbolic indication at an object and at the same time have no resemblance of it.

2.2. The triple cognitive-expressive modus is formed primarily by unconditional colour signs showing the greatest possible resemblance
to a reflected object. As an example, when reproducing natural objects in colour for scientific purposes an adequate reflection of
their colour properties with use of unconditional signs is needed. Similarly, when reproducing coloured works of art with scientific
purposes in mind the maximum colour resemblance of a reproduction to the original is needed. Here one is up against a paradoxical
metamorphosis: a work of art is represented by the expressive-cognitive colour modus, but its reproduction (copy) constitutes the
cognitive-expressive colour modus .
Such is indeed the principal difference between an original and its reproduction (copy).

2.2.1. Cognitive-expressive colour modi are used in popular scientific information when studying arts. They are formed through the use
of associative signs-indexes that only vaguely resemble an original. The last fact seems quite natural because it is an evidence of an
object and not a complete colour resemblance of it that is of importance inpopular information.

3.1. The dual expressive colour modus has no cognitive function. This fact indicates
that it deals with various kinds of abstract art, such as abstract painting, original (self-dependent) music of colour, decorative art
using abstract coloured forms, abstract coloured poetry and some other non-informative kinds of colouring art. Our understanding of both
theory and practice of abstract art is given in [2-4].

Studying the normative theories of colour music harmony, from Aristotle to Kandinsky, we have noticed that both painters and theoreticians
of abstract art tried persistently to explain purely expressive art using cognitive images and notions. Did they seek to make up for the
lack of cognitive function? Such an attempt implies setting up prerequisites for conceptual-symbolic art with a time lag between expressive
and cognitive functions, i.e. abandoning the purely expressive modus.

3.2. The triple expressive-cognitive colour modus is traditionally realized in all the kinds of fine arts. On the way from the art that
reflected reality through naturalistic images (e.g., Dutch painting of the 17th century) to the most conventional conceptual-symbolic art
(such as symbolic painting of the 20th century), from Snyders to Malevich, colour has transformed from an inseparable indication of a real
object into a separable independent symbol having a cognitive-expressive meaning. This very significant metamorphosis contains inexhaustible
latent potentialities of complex modi. Local colour that has both cognitive (as a symbol) and expressive (as an emotion source) functions,
making a single composition with other modi (including black-and-white ones), results in novel colour images that are more rich in both
cognitive and expressive respects.

4. CONCLUSION

The above modus system for colour images can serve a visual aid for structural analysis of cognitive and expressive colour functions in
both information and art. Such an analysis sets the stage for formulating the basic principles of purposeful forming of colouring images.

4.1. Principle of activation of communicatory colour means
The essence of this principle is in communicatory colour differentiation of the basic content for operating the perception process. The
efficiency of the principle makes itself evident in design and advertising business and also in book and computer text design.

4.2. Principle of refining and extending colour cognitive imagery of information
The essence of this principle is in activation of the set of colour qualities that are of importance for cognition. The principal purpose
when forming an image lies in cognition sphere. The expressive significance arises as the response to aesthetic qualities of both the
content and the way of its realization. The principle is efficient in scientific (and popular scientific) analysis of art, in documentary
reproducing various coloured objects (esp. works of art), in all those types of advertising where realistic images are used.

4.3. Principle of multifunctional expressive colour designation
For this principle there are several functional levels, of realization depending on the purposes to be sought.

4.3.1. Principle of bright decorative colouring is easily understood and gives pleasure to the vast majority of any audience. Its efficiency
makes itself especially evident in decorative design of visual objects for children, various festivals and optimized advertising.

4.3.2. Principle of art colour imagery has more serious goals and can be used when solving more complicated problems. It is realized in all
the spheres and types of visual art without exception: in painting, theatre, cinema and TV, book and computer artwork etc (for details see [2,5,6].

4.3.3. The quintessence of an expressiveness on the whole lies in the principle of musical colour expressiveness. One cannot formulate it
in words. As v/as stated before, any formulation of abstract-expressive art converts it immediately from the sphere of free expression of
feelings to the area of game rules and regulated emotions. Nevertheless one can speak about two forms, the static and dynamic ones, of
temporal realization of colour harmony. Being asked why the dynamic music of colour has lagged in its evolution behind the music of sound
one may say just as Louis-Bertrand Castell did: music of colour needs its own instruments. Nowadays there are composers dealing with music
of colour. So the time is ripe to bring this problem to both minds and hearts of magicians of today's electronics.